I realized, while on my youtube archive edit run, that IABot does not recognize dead youtube links. It incorrectly marks all youtube pages as "live", even if the video is gone. See https://en.wikipedia.org/w/index.php?title=User:Rlink2/sandbox&action=history - i think the first link (https://www.youtube.com/watch?v=Rtm909-d8uo) is dead, but it is marked as live instead.

In the meanwhile, I'm manually marking dead youtube videos as dead and replacing them with a Wayback reference.